Suspension bridge



Oct. 30, 1951 H. W. SUMNER SUSPENSION BRIDGE Filed Sept. '7, 1945 ATTORNEY Patented Oct. 30, 1951 SUSPENSION BRIDGE Henry W. Sumner, Seattle, Wash., assigner to Walter E. Irving, Long Island City, N. Y.

Application September 7, 1945, Serial No. 614,854

3 Claims.

This invention relates to a suspension bridge and an object of this invention is to provide a suspension bridge wherein the possibility of developing undulations of dangerous magnitude is reduced to a minimum.

Another object is to provide a suspension bridge having means for absorbing or damping small vertical undulations or vibrations and dissipating their energy as heat so that these small vertical undulations or vibrations will not become cumulative and attain a great enough magnitude to seriously damage or destroy the bridge.

Another object is to provide a suspension bridge comprising a plurality of end to end, pivotally articulated, suspended bridge sections, each bridge section being substantially rigid and non-ilexible vertically whereby vertical undulations in the bridge will be manifested by changes in relative alignment of the bridge sections rather than by vertical flexing of said bridge sections and said bridge sections having their adjoining articulated end portions interconnected by damping means that will yieldingly resist relative changes of alignment of said bridge sec` tions in such a manner as to damp and suppress and dissipate the energy of forces tending to produce Vertical undulations thereby preventing the building up in the bridge of harmonious motions of dangerous magnitude.

Another object is to provide a suspension bridge comprising a plurality of relatively rigid bridge sections suspended from overhead cables and articulated in end to end relation and interconnected by friction means so applied as to frictionally resist changes of alignment of said bridge sections produced by vertical undulations in the bridge.

Other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings.

In the drawings:

Figure 1 is a diagrammatic View showing a plurality of relatively rigid bridge sections suspended in end to end relation and interconnected by undulation damping means in accordance with this invention.

Fig. 2 is a View similar to Fig. 1 showing adjacent end portions of two of the bridge sections with the damping means applied thereto in a different manner.

Fig. 3 is a side view of one type of damping means that may be used in the manner illustrated in Figs. 1 and 2.

Fig. 4 is a sectional view of said damping means taken substantially on broken line 4--4 of Fig. 3.

Fig. 5 is a diagrammatic View similarto Figs.

1 and 2 but showing a different type of damfi- Like reference numerals designate like parts throughout the several views.

' In Fig. 1 of the drawings the numeralsI 8, 9, IIJ and II designate four sections of a suspension bridge, which it will be understood may be composed of any desired number of sections. The bridge sections 8, 9, I0 and II are all suspended from suspension cables I2, one of which is shown in Fig. l, by tension members I3. Each bridge sections, 9, Ill and II is of relatively rigid noniiexible construction so that, as a unit, it is not capable of vertical iiexing movement. The bridge sections may be any suitable type of truss construction, as shown in the drawings., or they may be of other form. In constructing or repairing the bridge it is contemplated that these bridge sections can Abe handled as units and elevated into position and secured together after the cables I2 are properly installed. Obviously sections can be removed from and installed in such a bridge without disturbing other sections in the bridge.

The adjoining end portions of the several bridge sections are articulated by pivot means I5. A bridge, made up of any desired number of bridge sections will be provided with a continuous decking I4 to carry trai-lic. Preferably a portion of this decking or all of said decking will lbe of open mesh construction such as a steel grating that is capable of carrying the required loads. Such a grating construction will be less affected by suction lift and pressure resulting from generally horizontal winds passing thereover than a solid or imperforate decking would be. The-use of this steel mesh type of decking is desirable but not essential in a suspension bridge constructed in accordance with this invention, as the damping means herein provided will suppress undulations of dangerous magnitude irrespective of the type of decking used in the bridge.

The decking I4 has suiiicient flexibility at the locations of the pivotal connections E5 between the bridge sections so as to allow some movement in these pivotal connections I5. Hence vertical undulations in the bridge will be manifested chiefly by angular movement in these pivotal connections I5.

In accordance with my invention I provide damping means for resisting relative angular movement in the pivotal connections I5 and relative change of alignment between the adjacent bridge sections and for dissipating the energy which tends to produce cumulative vertical undulations in the bridge. c

One energy dissipating device that can be used for this purpose is a friction device more clearly shown in Figs. 3 and 4. This device comprises two sets of friction plates I6 and I'I mounted for pivotal movement on a hub member I8 and havof 'saiid two "bridge sections.

ing friction discs or washers I9 interposed between them.

The plates I6 Aand I1 with theiriction washers I9 interposed between "them are lild in fr'ictional engagement with each other 'by a spring 2|.

The spring 2| is disposed between washers y 22 on the hub member I8 and is adjustably supported by nut means 23. A head 24 is pr'vifd on the end of the hub member I8 opposite .the nut means 23. I Y Y Adjustment of the pressure o'f `the 'spi'ng 2| by nut means 23 will adjust the loedfon Fall idf the friction Washers I9 and plates I6 and Il in the friction unit thereby varying the resistance to movement oiered by "said unit. Obviously the *number :of'plates and y7fri'ctfi'cl1`f1 washers infdne of these friction Aunits inlay b'e 'varied '-'as fdesi'red.

The plates le and lf 'extend outwarly from the mit 'member *all "to form leverarms and 'sa'ii 'plates may taper, asshown. fifhesefplates 'ffqrth adequate heeft radiating "means fto radiate tot'h'e "atindsphere any heat generated by the'fr'ictin devices `YThese `-`plates le and F1 may iloe posi- Ytionei at 'any desired angle vrelative to each-'other vvheniin use. A

The plates I' and Il are 'connected with the `end portions of `two adjacent bridge sections v-in "such a Y"manner ftha't relative angular movement able shackle or bracket means 25 'with 'the lend `pci'rtio'ns 'of the adjacent bridge sections.

Another' `way 'of 'applying Jsaid friction'device Sto 'th-'e 'bridge "sections is t'o in'v'ert the g'friction "0T damping ldevice 'as 'respects ithe snowing `in Figl 'and connecttheisainewith the Lendpor'tiorls `o`f l the ybridge 'spans by brackets 26 as shown in Fig. 2. Y

`Both Fig. 1 Tand Fig. '2 'sh'o'w an 'arrangement Cin 'which leverage' is 'provided "so lthatasligh'tan- Agl'la'r movement 'of the 'bridge .spans `relative to eachother 'will Jp'ro'diice Aa :greater relative angli- 'lar 'movement di ithe 'friction'plates "tahd FI.

I Fig. 5 Vdiagrarum-atlcally "illustrates h yarariiie lxiie'a'ns'of 'dash pot type "interconnected between -the"adjacent end'sf two bridge sections in J"such a Arrranirerasto resist relative angularmovemeiit 'means may comprise aliquid 'iight hydraulic 'c'ylinder 21 connected with one bridge se'cticn'll and lled with liquid, asbiljand havin'f'g'a"lo'sf-lyTitting piston fth'at is 'cohnected'bya'pistonfrl 29 'with an ad'jacentbridg'e"section "IIL 'V'Ilepiston 28 may'h'ave a passageway 3'0 el verys'rn'ail cross sectional area 'eiite'ndi'n'g therethrough to those nereinjdeseribed Y The -f'oregoing description 'arid 'accompanying drawings 'disclose preferred enbciiments .d'f ,75'

invention 2bulfrt'viill beunderstoethat'wise closure is merely illustrative and that changes may be made within the scope and spirit of the vfollowing claims.

I claiml:

1. In a suspension bridge, suspension cable .means a plurality of bridge sections suspended 'from said suspension cable means in end to end relation, each bridge section being rigid vertically; horizontal transverse pivot means pivotall'y r'rinectingadj'oining end portions of said 'bridgeV 'sections together; energy dissipating rdam-ping meansfspaced from said pivot means interconnecting adjacent end portions of said bridge sections adapted to yieldingly resist all relative vertical pivotal movement of the bridge sections with wh'ich said 'da'r'n' 'pin'g 4means iis Zconlne'cte'd'; -an'd alco'nt'inu'ous bridge dec'kcarrielby 'said rbridge fse'ctions, said bridg'e -deck 'being Eca'- adjoining pivotally connected endsiof sai'dbiidge f'secti'ons. Y

`-I2.111 fa suspension bridge, 'suspension cable means; aplurality *'of bridge sections suspended 'from 'said f-susp'en'sio'n cable 'means and disposed ine'n'd to'end'relation, each bridgefs'ec'tion being 'substantially -rigid `1in vertical directions; -contin'- uous bridge deck mean's carried vby said bridge s'ectionsj'horizontal epivot means positioned fad- "jacent the plane 1of said b'rlidge 'deck Vmeans and extending Tcrosswise of s'ai'cl bridge 'sections and 'pivotally interconnecting 'adjacent end port-ions "of 'said bridge lsec'tio'ns; and friction means ffspa'c'ed from-saidV pivdt'ir'ieans and interconnected 'fb'etween aljacentfend portions-'of `said bridge sections operable 'toyielding'lyresist relative vertical 'pivotal Imovement 'of the bridge' sections 4with which it "is 'connected and suppress Vertical `u'n asiaticas "or vthe bridge.

3. "ln "a suspension ibridge, suspension cable rlr'ean's; afplura'lity of bridge y'sections 'suspended from 'se'i'dsuspension cable means inend to 'end relation, each di saidbridge Vsections being rigid wertically; transverse Ahorizontal `pivotlne'ans 'directly connecting adjoining 4end 4portionsof said v' "bridge sections together vfor lrelative lvertical movement; and 'energy Adissiplating damping "Inea-nsfinterposed -between 'adjacentfend portions "of 'said lbridge sections 'and spaced from 4said 'transverse pivot means and Yconnected with sala Kbridge 'sectons 'and `providingresistance to `all relative angular lnovemehtcf said 'bridge 'sections about said pivot means, whereby cumula- "ti've "vertical undulating 'movement xof said'bfdge sections iis suppressed.

v REFERENCES CITED The ,following .references are `ci record in the .Ifileoiitlrismaten-t:

UNITEDsTATEs PA'I'ETS 'Niiniber n Name Date 1110546 j'carnbell Dec. '187'0 '27939-27 iilmery Aprf29j1'e'79 1,146,283 Rush July 13, i915 figaeaise winnen vi'vevsae,11929 nissen-sii 'Rus'h` Jan. '31, 193e 2,152,896 Maddoek i Y sept. 4, "l1-93's lz-,eeaeeiiviaidock Oct 5, 11943 .12,358,672 Y. var'tia, saperla, 1942i ascesa? vllrhssnafll .neb. 6.11945 v -QTHERQREEERENGES 

